BackgroundStudies directed at understanding the demography and population dynamics of corals are relatively scarce. This limits our understanding of both the dynamics of coral populations and our capacity to develop management and conservation initiatives directed at conserving such ecosystems.MethodsFrom 2012 to 2014, we collected data on the growth, survival, and recruitment rates of two common Caribbean coral species, the stress-tolerant Orbicella annularis and the weedy Porites astreoides. A set of size-based population matrix model was developed for two localities in Northeastern Puerto Rico and used to estimate population growth rates (λ) and determine the life cycle transition(s) that contribute the most to spatiotemporal differences in λs. The model was parameterized by following the fate of 100 colonies of each species at the two sites for two years.ResultsOur data indicate that spatial variability in vital rates of both species was higher than temporal variability. During the first year, populations of O. annularis exhibited λs below equilibrium at Carlos Rosario (0.817) and Palomino (0.694), followed by a considerable decline at both sites during the second year (0.700 and 0.667). Populations of P. astreoides showed higher λs than O. annularis during the first census period at Carlos Rosario (0.898) and Palomino (0.894) with a decline at one of the sites (0.681 and 0.893) during the second census period. Colony fate in both species exhibited a significant interaction with respect to location but not to time (G2 = 20.96; df = 3 for O. annularis and G2 = 9.55; df = 3 for P. astreoides).DiscussionThe similar variability of λs as well as the similar survival rates for both species during the two-year census period (2012–2014) show similar variability on demographic patterns in space and time. Our results suggest that location rather than time is important for the resiliency in coral colonies. Also, P. astreoides will show higher resistance to disturbance in the future than O. annularis.

Graduate students in the science, technology, engineering, and mathematics (STEM) disciplines struggle with developing research agendas that balance the overall goals of their work with questions of civic concern. The Earth Stewardship Initiative helps to resolve this disparity. Furthermore, connecting STEM research to civic concerns increases the relevance of research and facilitates the development of cross-disciplinary approaches. We describe how STEM graduate students can incorporate Earth Stewardship into their research, identify opportunities for educational institutions to support such research, and discuss the potential benefits of, and barriers to, linking Earth Stewardship to graduate-level studies. In a nutshell:• The implementation of a research agenda that is consistent with the Earth Stewardship Initiative requires transformation of the current academic culture • Graduate students and faculty members can be important actors in the transformation, although broader, departmentlevel support is crucial in facilitating this process • Earth Stewardship projects can deliver benefits to graduate students, including enhanced professional development and increased employment opportunities • Supporting Earth Stewardship in graduate training programs can also benefit academic departments by improving funding prospects and increasing the relevance of research to society

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The incidence and spatial distribution patterns of Caribbean Yellow Band Disease (CYBD) on the important frame-builder coralMontastraea faveolatawere assessed by counting, tagging, and mapping all diseased and healthy colonies for one year in each of three 100 m2quadrats on two inner, mid-shelf, and shelf-edge reefs off La Parguera, Puerto Rico. Healthy colonies were checked every month from January to December of 2009 to monitor disease spread within each quadrant. Incidence increased significantly from winter (0.7±0.8% SE) to summer (1.5±1.1% SE,n=23, Sign Test;Z=2.40;P=0.01). Mid-shelf reefs had the highest host abundance and showed significantly higher CYBD incidence (2.1±1.4% SE,n=14) compared to the other zones (H=9.74; df=2;P=0.04). The increased incidence in the summer suggests that warmer months favor development of CYBD onM. faveolata. Results showed aggregated patterns of CYBD when all colonies (i.e., healthy + diseased) at the spatial scales sampled were analyzed on each reef. This suggests facilitation of disease spread between aggregated colonies within populations. Similar stressful conditions then might trigger the disease in susceptible, aggregated colonies harboring the potential pathogens.